Ninth deep sea search for MH370

As the ninth underwater search for Malaysia Airlines flight 370 begins, authorities have yet to find any signs of the wreckage, prompting further speculation that the search may be altered later this week.

The autonomous underwater vehicle, Bluefin-21, has so far searched about two-thirds of the focused underwater search area - a 10km radius around the second towed pinger locator detection from April 8 - with no significant results.

Up to 10 military aircraft and 11 ships are assisting in Monday's search, covering about 49,491 square kilometres, about 1741 kilometres northwest of Perth.

But weather conditions are deteriorating, particularly in the north of the search area as Tropical Cyclone Jack tracks south, and widespread showers are developing with isolated thunderstorms.

Australian ambassador to the US Kim Beazley said private contractors and more underwater search vehicles could soon be used in the search.

The idea was previously flagged by Prime Minister Tony Abbott that if the plane was not found in the Indian Ocean by mid-week, searchers would stop and reconsider tactics.

The air search might be adjusted, Mr Beazley told CNN's Sunday morning political program, State of the Union with Candy Crowley.